Understanding crypto prices
The price is whatever someone just paid.
Bitcoin's price isn't a number on a chart — it's the most recent trade across a fragmented set of exchanges.
Where the price comes from.
Unlike stocks, crypto has no single venue. Bitcoin trades on dozens of exchanges simultaneously — Coinbase, Binance, Kraken, OKX, Bybit, regional ones besides — and each has its own order book and slightly different price. Aggregators publish a volume-weighted average; that's the figure on most converters. Your actual price depends on which exchange, which side of the order book, and how big your order is.
Volatility, in perspective.
A 5% move in a single day is unremarkable for bitcoin. The same move in a major fiat pair would make headlines. Annualised volatility of bitcoin is several times that of equities, and smaller coins move several times more than that again. Any calculator that converts crypto to fiat is showing a snapshot — refresh in five minutes and the number will have moved.
Market cap is not money in.
A coin with a $1 billion "market cap" doesn't have a billion dollars sitting somewhere. The figure is just price × supply — a back-of-the-envelope number. Try to sell every coin at the current price and the price collapses long before you're done. Slippage matters, especially on thinly traded coins.
market cap = price × circulating supply
Stablecoins and the dollar peg.
USDT, USDC and other stablecoins aim to track the US dollar one-to-one. Most of the time they do, but not always: in times of stress they've traded as low as $0.85. The peg is a target, not a guarantee, and the mechanism behind it differs by issuer (collateralised reserves for USDC, algorithmic for some failed projects).
Why on-chain price ≠ exchange price.
A swap on Uniswap and a trade on Binance can quote different numbers for the same token at the same instant. Bots arbitrage the gap, but in volatile moments the spread widens before the bots catch up. If precision matters, name the venue.